A spreader is a scattering attachment used with planting tools such as air drills which distribute seed, fertilizer or other granular material in airflow conduits across the width of the planting tool. The spreader is associated with delivery tube, positioned either at the outlet or just inside or outside the outlet. Its purpose is to deflect and redirect seed into a broader area than the row which would be produced by the delivery tube alone. The greater the spread and uniformity of seed placement within the planting furrow, the better seed bed utilization achieved.
Seed delivery spreaders currently in use generally comprise an obstruction in or near the outlet of a seed delivery tube which divides the delivery stream into two separated streams. The spreader may be a block with angled faces, or simply a bolt protruding into the seed stream.
An example of a common type of spreader is a Standard spreader produced by Concord which includes a casting having two angled upper surfaces which meet at a central line positioned in the product stream inside the delivery tube. The casting is bolted to the front interior surface of the delivery tube, generally above the product stream. The common feature to this and equivalent designs is an obstruction essentially perpendicular or at a high angle to the travel of the product stream against which the seeds and other products collide at significant velocity. The seeds tend to separate into two separate streams about the obstruction, and are placed in the furrow essentially in two separate rows. Further, the force of the collision with the spreader causes fracturing and splitting of an undesirably large percentage of the seed.
Depending on soil conditions and other parameters, different ground opening tools will be used which create furrows of different widths. A spreader produced by FarmLand includes replaceable castings of different widths to place in the delivery tube on the front interior surface. Different casting shapes determine the amount of separation resulting between the seeded rows. The casting has angled faces acting on the product stream which divide the seeds into two separate streams. The planting pattern is not scattered but is still divided to form separate rows. Growth patterns using this system exhibit this uneven seeding pattern. While this design achieves variation in the delivery pattern, a different tool must be obtained and installed each time a different spread width is desired to make the change. Further, the seeds still must collide with a nearly perpendicular obstruction surface and will suffer damage.
A Flexi-Coil design provides a spreader formed integrally on the rear interior surface of the delivery tube adjacent the outlet. The deflector has a rounded convex shape and does not present the perpendicular surface to the seed stream. However, this design is only suitable for producing a narrow seed scatter pattern since it is within the delivery tube, and the product spread is not as even as desired.
A design from JR Welding discloses the use of a rectangular extension surface extending from the rear interior surface of the delivery tube behind the product stream. The spreader is crimped to conform to the outlet and to have a high central ridge from which the surfaces are angled laterally. The spreader is welded onto the outlet at a small angle to the product stream compared to other prior art devices. The gentle angle of this spreader to the product stream does cause less shock damage to the seed than other spreaders, but the high central ridge tends to divide the seed stream quite distinctly into two rows which are seeded heavily with very little product deposited towards the central region of the furrow. The outlet is also shielded by a seed boot positioned close to the spreader. Forward deflection of seed is limited as a result. This planting pattern is not desired. No adjustment to the spreader position is possible.
The formation rows of seed or fertilizer reduces the amount of product which can be applied. Seed does not benefit from over crowding, and fertilizer and other products may accumulate in unwanted concentrations which may cause damage.
Rather than planting in two separate rows, a more even scatter pattern is desired for fuller utilization of the soil. It is desired to provide a spreader which provides even scattering of seed delivery without forming distinct rows. If even application of seed and fertilizer can be assured, greater quantities of product can be applied to obtain more efficient soil usage without crowding or burning seed. It is also desired to be able to vary the width of the seed applied to match the furrow. Factors such as air flow, and ground conditions vary the effect of the spread width caused by spreaders. An adjustable spreader would allow seeding to be adapted to the specific conditions to match the spread to the furrow. It is further desired to achieve this delivery without causing shock and seed damage.